Preparation of ammonium polythiomolbydate

ABSTRACT

A novel composition of matter, ammonium polythiomolybdate, having the empirical formula 3MoS.sub.4 .2NH.sub.4 OH.

United States Patent Knrtak et a].

PREPARATION AMMONIUM POLYTHIOMOLBYDATE Inventors: Charles R. Kurtak,Bishop. Calif;

Laurence D. Hartzog, Kearney.

Appl. No.: 370,851

Related U.S. Application Data Continuation-impart of Scr. No. 95.990.Dec. 7. I970. Pat. No. 3.764.649.

U.S. Cl. 423/517 Int. Cl. C0lb 17/98; COlg 39/00 Field of Search423/56-58,

[451 Apr. 8, 1975 [56] References Cited UNITED STATES PATENTS 2.556.2556/1951 Carosella 423/58 2.892.74l 6/1959 Spengler et al. 423/5653.173.754 3/1965 Kurtak 423/57 3.764.649 l0/l973 Kurtak et al 423/56Primary E.\'aminerEarl C. Thomas Attorney, Agent, or FirmFrederick J.McCarthy [57] ABSTRACT I A novel composition of matter, ammoniumpolythiomolybdatc, having the empirical formula 3MoS .2N- H OH.

1 Claim, No Drawings PREPARATION OF AMMONIUM POLYTHIOMOLBYDATE Thisapplication is a continuation-in-part of US. application Ser. No.095,990. filed Dec. 7, 1970 by C. R. Kurtak and L. D. Hartzog, now US.Pat. No. 3,764,649.

This invention relates to the preparation of a molybdenum compoundhaving the empirical formula 3MoS,'2NH OH and designated as ammoniumpolythiomolybdate.

It is an object of the present invention to provide a novel compound ofmolybdenum.

It is a further object of the present invention to provide a method forpreparing ammonium polythiomolybdate.

Other objects of the present invention will be apparent from thefollowing description and claims.

The novel compound, ammonium polythiomolybdate, 3MoS -2NH,OH, can beprepared by a process which comprises reacting in an ammoniacal aqueousenvironment, ammonium molybdate, ammonium sultide, and elemental sulfur.The reaction is conducted under pressure at elevated temperatures.

A novel process for producing ammonium polythiomolybdate, 3MoS 2NH OH,comprises heating under pressure an aqueous ammoniacal solution ofammonium molybdate and ammonium polysulfide (elemental sulfur dissolvedin ammonium sulfide) to cause reaction therebetween and the productionofa dark red crystalline precipitate. Suitable reaction temperatures arein the range of about 175C to 220C and suitable pressures are from about300 psig to 700 psig.

The above process corresponds to the following equation:

The aforedescribed process can be practiced by providing an ammoniacalammonium molybdate solution by dissolving molybdic oxide, molybdic acidor other ammonium molybdate salts, e.g., ammonium paramolybdate andtetramolybdate in sufficient ammonium hydroxide. either at ambient orelevated temperatures and pressures to obtain a solution with a pH of atleast about 9.0.

To the aforedescribed solution is added ammonium polysulfide, i.e.ammonium sulfide in which elemental sulfur is dissolved. and thisreaction mixture is heated in an autoclave to a temperature in the rangeof 175C to 220C and maintained in this temperature range, underpressures of from 350 psig to 700 psig for from about l to 2 hours,whereby a precipitate of dark, blood-red crystalline material isobtained. This material, ammonium polythiomolybdate 3MOS,'2NH,OH, isinsoluble in cold water or aqueous ammonia and acetone, but is solublein hot water or aqueous ammonia (80C) and produces therein an orangecolored solutron.

Upon heating in air at 500C, ammonium polythiomolybdate is oxidized to MWith heating in an atmosphere of hydrogen at 390C, ammoniumpolythiomolybdate is converted to poorly crystalline M05 at 1080C, M0 8is formed. No other intermediate compounds are formed through thistemperature range.

Characteristic properties of this novel compound are set forth in thefollowing table:

Indices of refraction n'y 2.3; na 2.2 (negative sign of elongation)diamagnetic "obs.A

Magnetic moment X-ray Difi'raction Data* (rel.)obs.**

bi l-mu- L86. L831 L800 L743 L692 L643 *using Copper K01 radiationobserved relative intensity The following example will furtherillustrate the present invention.

EXAMPLE I Fifty (50) grams of molybdenum (as molybdic oxide) weredissolved in 500 ml of 3 Molar NH OH. The molybdic oxide employed wascontaminated with tungsten and the ratio of Mo to W0 in the resultingsolution was approximately 3:l. Added to this solution were 425 ml of 42percent ammonium sulfide solution in which had been dissolved 46 gramsof flowers of sulfur.

The foregoing reaction mixture was digested in an autoclave at 198C for2 hours. The pressure developed in the autoclave was 350 psig. A dark,blood-red crystalline precipitate was obtained which was analyzed andfound to be ammonium polythiomolybdate, 3MoS -2NH OH. The yield ofmolybdenum was 96.5% basedon the amount of molybdenum employed. Theprecipitated material was in the form of six-sided prisms(pseudo-hexagonal) with jagged bases averaging microns in length withaverage diameters of 15 microns.

When this material was roasted in air and converted to M00 the oxideproduct was found to have a Mo to W0 ratio of 8300zl.

Thus, the production of ammonium polythiomolybdate in accordance withthe present invention, provides a highly selective precipitation ofmolybdenum from a tungsten contaminated solution.

A further example is provided to illustrate a novel method of producingMoS from ammonium polythiomolybdate.

3 4 EXAMPLE 1] X-ray Difraction Data" "obs.A '(reL) obs.** Ten l) gramsof ammonium polythiomolybdate I were heated in a tube furnace at 600 Cunder a hydro- 1 ()5 gen atmosphere for 2 hours. 4.85 2

The resulting product, when analyzed. shows the stoi- 5 chiometry of M05X-ray diffraction shows only single 1 j phase M08 1 Surface areameasurement showed 20 square meters 5'8 per gram. 2.86 0.5-1.0 As shownby Example II. the novel material of the 10 present invention can beused in the production of :5 1 M05 which material is useful as alubricant and cata- 2.45 1.0-2.0 lyst. 10-10 2.0-7.0 What is claimed is:r 2.36 2.03.0 1. As a novel composition of matter. ammonium 2.2872.0-3.0

. 7 polythiomolybdate, having the formula 3MoS '2N- g8: 8}? H OH and thefollowing characteristic properties 015 16 1.94 0.54.0 1.91 0.84.2 1.8950.54.0 20 1.863 0.5-1.0 1.831 0.5-1.0 Infrared absorption maxima 539.505337. 278 (CM l 1.800 0.3 Specific gravity 2.57 1.743 l-Z Crystallinestructure monoclinic L691 054,0 lndices of refraction n'y 2.3: na 2.2L641 0 4-9 7 (negative sign of elongation) I Magnetic moment diamugentici i y Difraction Data* ,(reL) ohs Observed relative rnlcnslly.

8.76 lo 8.27 6 l=

1. AS A NOVEL COMPOSITION OF MATTER, AMMONIUM POLYTHIOMOLYBDATE, HAVINGTHE FORMULA 3MOS4.3NH4OH AND THE FOLLOWING CHARACTERISTIC PROPERITIESINFRARED ABSORPTION MAXIMA 539,505 337 278 (CM-1) SPECIFIC GRAVITY 2.57SPECIFIC GRAVITY CRYSTALLINE STRUCTURE MONOCLINIC INDICES OF REFRACTIONNY=2.3; NA=2.2 NEGATIVE SIGN OF ELONGATION) DIAMAGENTIC DOBS.A ''(REL.)OBS.** 8.76 10 8.27 6 5.44 5 5.16 14.93 0.5 4.85 2 4.35 0.5-1.0 4.230.1-0.5 4.11 0.1-0.5 3.34 1.0 3.19 2.0 2.91 3.0 2.86 0 2.75 0.5-0.1 2.580.5-1.0 2.52 1.0-1.2 2.45 1.0-2.0 2.42 2.0-3.0 3.37 2.0-3.0 2.362..0-3.0 2.287 2.0-3.0 2.04 1.0-2.0 2.04 1.0-2.0 2.01 8.0-1.2 1.990.5-1.0 1.94 0.5-1.0 1.91 0.8-1.2 1.895 0.5-1.0 1.863 0.5-1.0 1.8310.5-1.0 1.800 0.3 1.743 11.692 0.5-1.0 1.643 0.3-0.7